KR20200102443A - Titanium oxide powder and dispersion and cosmetics using the same - Google Patents

Abstract

The titanium oxide powder of the present invention is a titanium oxide powder having a BET specific surface area of 5 m ² /g or more and 15 m ² /g or less, wherein the titanium oxide powder includes polyhedral titanium oxide particles having 8 or more faces, The L value in the Lab color space is 75 or more.

Description

Titanium oxide powder and dispersion and cosmetics using the same

The present invention relates to a titanium oxide powder suitable for cosmetics, and a dispersion and cosmetics using the same.

This application claims priority based on Japanese Patent Application No. 2017-253790 for which it applied to Japan on December 28, 2017, and uses the content here.

Titanium oxide particles are excellent in light reflection properties, ultraviolet shielding properties, and hiding power. Therefore, titanium oxide particles of submicron size to micron size are used in base makeup cosmetics such as foundations.

As titanium oxide particles suitable for cosmetics, spherical anatase type titanium oxide particles having an average particle diameter of 0.1 μm to 5 μm, for example, have been proposed (for example, see Patent Document 1).

Further, spherical primary particles are accumulated, and spherical rutile type titanium oxide particles having an apparent average particle diameter of 100 nm or more are also proposed (for example, see Patent Document 2).

Patent Document 1: Japanese Laid-Open Patent Publication No. 2013-28563 Patent Document 2: Japanese Laid-Open Patent Publication No. 2014-15340

However, there has been a demand for further improvement of titanium oxide particles capable of reducing the bluishness peculiar to titanium oxide particles while having hiding power and transparency.

The present invention has been made in view of the above circumstances, and when applied to the skin, a titanium oxide powder having excellent whiteness, which can reduce the bluishness peculiar to titanium oxide particles, while having a hiding power and a sense of transparency, and using the same It aims to provide dispersions and cosmetics.

That is, the titanium oxide powder of the present invention is a titanium oxide powder having a BET specific surface area of 5 m ² /g or more and 15 m ² /g or less, wherein the titanium oxide powder includes polyhedral titanium oxide particles having 8 or more faces. And, it is characterized in that the L value in the Lab color space is 75 or more.

The dispersion liquid of the present invention is characterized by containing the titanium oxide powder of the present invention and a dispersion medium.

The cosmetic composition of the present invention is characterized by comprising the titanium oxide powder of the present invention and a cosmetic base.

According to the titanium oxide powder of the present invention, when applied to the skin, a titanium oxide powder having excellent whiteness, which can reduce the bluishness peculiar to titanium oxide particles while having a hiding power and a sense of transparency, and a dispersion liquid using the same, Cosmetics can be provided.

According to the dispersion liquid of the present invention, when a cosmetic composition containing this dispersion liquid is applied to the skin, it is possible to reduce the bluishness peculiar to titanium oxide particles while having hiding power and clarity.

According to the cosmetic composition of the present invention, when applied to the skin, it is possible to reduce the bluishness peculiar to titanium oxide particles while having hiding power and clarity.

1 is a schematic diagram showing a preferable example of an octahedral titanium oxide particle.
Fig. 2 is another schematic diagram showing a preferred example of octahedral titanium oxide particles.
3 is a diagram showing a scanning electron microscope image of titanium oxide particles of Example 1. FIG.
4 is a diagram showing a transmission electron microscope image of titanium oxide particles of Example 1. FIG.
5 is a diagram showing a simulation result of light scattering when the spherical titanium oxide particles are irradiated with light.
6 is a diagram showing a simulation result of light scattering when light is irradiated to octahedral titanium oxide particles.

Preferred embodiments of the titanium oxide powder of the present invention, and a dispersion and cosmetics using the same will be described.

In addition, this embodiment is demonstrated concretely in order to more fully understand the gist of the invention, and does not limit this invention unless otherwise specified. Omissions, additions, substitutions, and other changes may be made without departing from the spirit of the present invention.

[Titanium oxide powder]

The titanium oxide powder of the present embodiment is a titanium oxide powder having a BET specific surface area of 5 m ² /g or more and 15 m ² /g or less, wherein the titanium oxide powder includes polyhedral titanium oxide particles having 8 or more faces, The L value in the Lab color space is 75 or more.

(Specific surface area)

It is preferable that the BET specific surface area of the titanium oxide powder of the present embodiment is 5 m ² /g or more and 15 m ² /g or less, 5 m ² /g or more, and 13 m ² /g or less.

When the BET specific surface area of the titanium oxide powder is 5 m ² /g or more and 15 m ² /g or less, it is advantageous in that it can further reduce the bluishness peculiar to the titanium oxide particles while having a hiding power and a sense of transparency. In addition, when the BET specific surface area of the titanium oxide powder is less than 5 m ² /g, the sense of transparency decreases due to light scattering. On the other hand, when the BET specific surface area of the titanium oxide powder exceeds 15 m ² /g, the light scattering intensity of the short wavelength increases compared to the light scattering intensity of the long wavelength, and bluishness increases.

As a method of measuring the BET specific surface area, for example, a method of measuring from a nitrogen adsorption isotherm by a BET multi-point method using a fully automatic specific surface area measuring apparatus (trade name: BELSORP-MiniII, manufactured by Microtrac Bell Corporation) is mentioned.

The titanium oxide powder of this embodiment has an L value of 75 or more in the Lab color space. When the L value is within the above range, the whiteness of the titanium oxide powder is excellent. Therefore, the color tone when used for a cosmetic is excellent. On the other hand, when the L value is less than 75, the titanium oxide powder is colored dull yellow, and the whiteness of the titanium oxide powder is inferior. For this reason, the color tone when used for a cosmetic is deteriorated.

The L value is preferably 80 or more, and more preferably 85 or more.

The upper limit of the L value is preferably higher, but may be 100, 99, 95, or 90.

(Titanium oxide particles)

The titanium oxide powder of this embodiment is an aggregate of titanium oxide particles.

The shape of the titanium oxide particles of the present embodiment is a polyhedral shape having 8 or more surfaces.

Since the shape of the titanium oxide particles has 8 or more surfaces, light can be widely scattered, so when a cosmetic containing titanium oxide powder is applied to the skin, transparency and hiding power can be improved.

The content rate of the polyhedral titanium oxide particles having 8 or more faces in the titanium oxide powder is represented by the number% calculated according to the method described later. That is, the content rate of the polyhedral titanium oxide particles having 8 or more faces in the titanium oxide powder is preferably 50% by number or more, 60% by number or more, or 70% by number or more. The upper limit of the content of the polyhedral titanium oxide particles having 8 or more faces in the titanium oxide powder may be 80% by number, 90% by number, or 100% by number.

If the content rate of the polyhedral titanium oxide particles having 8 or more faces in the titanium oxide powder is 50% by number or more, when a cosmetic containing titanium oxide powder is applied to the skin, it has excellent hiding power and a sense of transparency, It is preferable from the viewpoint that the bluishness peculiar to the titanium oxide particles can be further reduced.

The content of polyhedral titanium oxide particles having 8 or more faces in the titanium oxide powder, i.e., the number %, is, for example, 100 titanium oxide particles observed by a scanning electron microscope (SEM). And it can be calculated by counting the number of polyhedral titanium oxide particles having 8 or more faces contained in these 100 pieces.

The average value of the maximum value of the line segment connecting two opposite vertices of the titanium oxide particles is preferably 100 nm or more and 1000 nm or less, more preferably 150 nm or more and 800 nm or less, and more preferably 200 nm or more and 750 nm or less. . In addition, the two opposite vertices are not adjacent vertices. That is, in the two vertices, the line connecting the vertex and the vertex is a line that passes through the inside of the particle without passing through the surface of the particle. The maximum value is obtained by the combination of the vertices at the farthest from each other.

As a polyhedral shape having 8 or more faces, it can be arbitrarily selected. Particles having a polyhedral shape are particles having a plurality of surfaces. For example, a shape such as an octahedral shape, a decahedron shape, a dodecahedron shape, an icosahedron shape, and a star shape can be mentioned. Each surface of the polyhedral shape may have substantially the same shape, or may include a plurality of different types of surfaces such as two types. The polyhedral shape may be a regular polyhedral shape or other polyhedral shape. For example, a shape such as an octahedron or a bisagonal pyramid is mentioned as a specific example. Among these, since light can be scattered over a wide range, octahedral titanium oxide particles are preferred. Hereinafter, a preferred example of the present invention will be described in detail using octahedral titanium oxide particles.

(Octahedral titanium oxide particles)

The octahedral shape described below is a three-dimensional shape surrounding the internal space with eight triangles as shown in FIG. 1. The eight triangles may all have the same shape, or two or more different shapes may be included, such as including two types of different shapes.

In addition, the tip of each vertex of the octahedral titanium oxide particles (points indicated by symbols A, B, C, D, E, F in Fig. 1) may be a pointed shape, a rounded shape, or a flat shape.

In the titanium oxide powder of the present embodiment, the content of the octahedral titanium oxide particles (hereinafter, sometimes abbreviated as "octahedral particles") is preferably 50% by number or more, and may be 60% by number or more, and 70 It may be more than the number %.

In the titanium oxide powder of the present embodiment, the upper limit of the content rate of the octahedral particles may be 80 number %, 90 number %, or 100 number %.

If the content of the octahedral particles in the titanium oxide powder is 50% by number or more, when a cosmetic composition containing the titanium oxide powder is applied to the skin, it has excellent hiding power and transparency, while the unique bluishness of the titanium oxide particles is obtained. It is advantageous in that it can further reduce.

The content rate of the octahedral particles in the titanium oxide powder can be calculated by, for example, observing 100 titanium oxide particles with a scanning electron microscope and counting the number of octahedral particles contained in these 100 particles. .

(Line segment connecting two opposite vertices)

The average value of the maximum value of the line segment connecting the two opposing vertices of the octahedral particle (hereinafter sometimes referred to as "the distance between the vertices" or the "distance between the opposite two vertices") is 300 nm or more and 1000 nm or less. It is preferably 320 nm or more and more preferably 900 nm or less, more preferably 330 nm or more and 800 nm or less, and most preferably 340 nm or more and 750 nm or less.

In addition, the average value of the maximum value means an average value obtained from the maximum value of the plurality of octahedral titanium oxide particles when one octahedral titanium oxide particle has a plurality of line segments connecting two opposite vertices and the maximum value of the length. do. In addition, the line segment connecting the two opposite vertices exists inside the particle, not on the surface of the particle.

The average value of the maximum value of the distance between the two opposite vertices is 300 nm or more and 1000 nm or less octahedral particles, compared with spherical and spindle-shaped titanium oxide particles, can widely scatter visible light. Therefore, it is presumed that the cosmetic containing the titanium oxide powder containing octahedral particles can reduce the bluishness peculiar to the titanium oxide particles while achieving both hiding power and clarity.

If the average value of the maximum value of the distance between the two opposing vertices of the octahedral particles is 300 nm or more and 1000 nm or less, when applied to the skin, the bluishness peculiar to titanium oxide particles can be further reduced while having excellent transparency. It is advantageous in that

If the average value of the maximum value of the distance between the two opposing vertices of the octahedral particles is 300 nm or more, light of a short wavelength is difficult to be scattered, and bluish coloration is suppressed, that is, the peculiar bluishness of the titanium oxide particles. It is preferable because it can reduce. On the other hand, when the average value of the maximum value of the distance between two opposite vertices in one particle of the octahedral particle does not exceed 1000 nm, excellent transparency is obtained, which is preferable.

The maximum value of the distance between the two vertices opposing the octahedral particles is measured by observing the octahedral particles with a scanning electron microscope (SEM). Specifically, for 100 octahedral particles, the maximum value of the distance between two vertices facing each particle is measured, and the arithmetic average of the obtained plurality of measured values is the maximum value of the distance between the two opposite vertices. It is an average value.

Here, when the octahedral particles do not aggregate as in the present invention, the distance between the vertices of one octahedral particle, that is, the distance between the vertices of the primary particle, is measured. On the other hand, in the case of comparing the present invention with other cases in which particles are aggregated to form agglomerated particles, the distance between the apex of the agglomerated particles, that is, the distance between the vertices of the secondary particles, may be measured. Examples of the aggregated particles include aggregated particles in which the particles aggregate to form an octahedral aggregate, and aggregated particles in which the octahedral particles aggregate. The same applies to the measurement of the maximum value (X) and the minimum value (Y) described later.

In addition, in the case where the tip end of the apex of the octahedral particle is a flattened surface, the center point of the flattened surface is used as the apex, and the maximum value of the distance between the two opposite vertices is set.

The maximum value of the length of the line segment connecting the two opposite vertices of the octahedral particle, for example, the line segment connecting the two opposite vertices (point A and point B in FIG. 1) (in Fig. 1) The maximum value of the length of the long axis (m) of the octahedral particle is taken as X (nm). On the other hand, the minimum value of the length of the line segment connecting the two opposite vertices is, for example, an octahedron, which is orthogonal to or approximately orthogonal to the line segment (long axis (m) of the octahedral particle in Fig. 1) relating to the maximum value. Of the line segment (short axis (n, o) of the octahedral particle in FIG. 1) connecting two vertices (point C and point E, or point D and point F in FIG. 1) opposite to the phase particle The minimum value of the length is referred to as Y (nm). At this time, the average value of the ratio of X to Y (X/Y) is preferably 1.5 or more and 3.0 or less, and more preferably 1.5 or more and 2.5 or less.

When the average value of the ratio (X/Y) is 1.5 or more and 3.0 or less, a cosmetic containing titanium oxide powder containing octahedral particles more effectively obtains the light scattering effect of the octahedral particles when applied to the skin. It is advantageous in that it can be used and the sense of transparency can be further improved.

The said substantially orthogonal means that two line segments (the major axis and the minor axis of an octahedral particle) intersect at an angle of 70° to 90°. In addition, with said substantially orthogonal, two line segments (long axis and short axis of an octahedral particle) should just approach and intersect, and two line segments (long axis and short axis of an octahedral particle) do not necessarily have to have an intersection.

It is preferable that the octahedral shape is a bisagonal pyramid in which two square pyramids share a square bottom surface. The octahedral shape in the present embodiment is preferably a shape in which two congruent square pyramids share a square bottom surface, and more preferably a shape in which two congruent square pyramids share a square bottom surface. The tip portion of the bisagonal pyramid may be pointed, rounded or flat.

In addition, in this embodiment, the side shape of a square pyramid is an isosceles triangle, and it is not an equilateral triangle. In addition, the maximum value (X) of the distance between two vertices facing the octahedral particle means the length of a line segment that gives a distance between two vertices existing in a direction orthogonal to the bottom surface of a square pyramid. In addition, the minimum value (Y) of the distance between the two apex which the octahedral particle opposes means the length of the shorter diagonal of the two diagonal lines of the bottom surfaces of two square pyramids.

Here, the distance between the two vertices will be described with reference to the drawings. 1 is a schematic diagram showing a preferred example of an octahedral titanium oxide particle in the titanium oxide particle of the present embodiment. For a plurality of vertices included in the octahedral particle, as the distance between the two vertices, as shown in Fig. 1, the distance between the point A and the point C (a), the distance between the point A and the point D (b), and point A Distance between point E and point E (c), distance between point A and point F (d), distance between point C and point D (e), distance between point D and point E (f), distance between point E and point F ( g), distance between point F and point C (h), distance between point B and point C (i), distance between point B and point D (j), distance between point B and point E (k), and point B There are 15 total distances between points F (l), between points C and E (n), between points D and F (o), and between points A and B (m). In Fig. 1, the distance between the two vertices facing the octahedral particle is the distance between the point C and the point E (n), the distance between the point D and the point F (o), and the distance between the point A and the point B (m). It is three of the. The maximum value of the distance between the two vertices facing the octahedral particle is the distance m, and corresponds to the maximum value (X) of the distance between the two vertices facing the octahedral particle. In addition, in FIG. 1, the line segment which connects the two vertices which oppose octahedral particles are substantially orthogonal to the line segment with respect to the maximum value X is a distance n and a distance o. Of the distance n and the distance o, the shorter one corresponds to the minimum value (Y) of the distance between the two vertices facing the octahedral particle.

The maximum value (X) (nm) of the distance between the two vertices facing the octahedral particles and the minimum value (Y) (nm) of the distance between the two vertices facing the octahedral particle are, for example, a scanning electron microscope ( SEM) can be used to measure by observing octahedral particles.

The ratio (X/Y) is calculated by observing the titanium oxide particles using a scanning electron microscope (SEM), and measuring the maximum value (X) and the minimum value (Y). For each of the 100 octahedral titanium oxide particles, the ratio (X/Y) is calculated, and a value obtained by arithmetic average of a plurality of values obtained is the average value of the ratio (X/Y).

(Average particle diameter converted from BET specific surface area)

The average particle diameter of the titanium oxide powder (hereinafter, also referred to as "BET conversion average particle diameter") converted from the BET specific surface area of the titanium oxide powder is preferably 300 nm or more and 1000 nm or less, and more preferably 310 nm or more and 800 nm or less. And, it is more preferably 320 nm or more and 700 nm or less.

The average particle diameter in terms of BET of the titanium oxide powder can be calculated by the following equation (1) when the shape of the titanium oxide particles is an octahedral shape.

BET conversion average particle diameter (nm) = 16240/(BET specific surface area (m ² /g) x ρ (g/cm ³ ))... (One)

In addition, in the above formula (1), ρ represents the density of titanium oxide.

Even if the titanium oxide powder contains titanium oxide particles of a shape other than the octahedral particles, when the titanium oxide powder contains 50% or more octahedral particles, the average particle diameter in terms of BET is calculated using the formula (1). Calculate.

(Average value of maximum value/average particle diameter in terms of BET)

The value obtained by dividing the average value of the maximum value by the average particle diameter of the octahedral particles converted from the BET specific surface area (average value of the maximum value/average particle diameter in terms of BET) is 0.5 or more and preferably 2.5 or less, and 0.7 or more and 1.4. It is more preferable that it is below, and it is more preferable that it is 0.9 or more and 1.3 or less.

If the (average value of the maximum value/average particle diameter in terms of BET) is less than 0.5, it is assumed that fine pores or the like exist in the titanium oxide particles, so that the refractive index as the particles is lower than the original value of the titanium oxide particles, and as a result, hiding power This may decrease. On the other hand, if the (average value of the maximum value/average particle diameter in terms of BET) does not exceed 2.5, when a cosmetic composition containing titanium oxide powder is applied to the skin, the light scattering effect by the shape of the titanium oxide particles can be obtained, resulting in a sense of transparency. Can be improved.

In general, the average particle diameter of the octahedral particles, which is converted from the BET specific surface area, is a line segment connecting two opposite vertices of the octahedral particles, which is measured by observing with an electron microscope when the octahedral particles are not aggregated. It roughly corresponds to the arithmetic mean value of the maximum value of.

Therefore, the closer the value of (average value of the maximum value/average particle diameter in terms of BET) is closer to 1.0, the more titanium oxide particles are not aggregated, and there are many particles present in the primary particle state.

On the other hand, when the primary particles aggregate to form octahedral particles, the arithmetic average value of the maximum value of the line segment connecting the two opposite vertices of the octahedral particles, measured by observation with an electron microscope, is the BET specific surface area. It does not coincide with the average particle diameter converted from. Therefore, when primary particles aggregate to form octahedral particles, the average value of the maximum value/average particle diameter in terms of BET exceeds 2.5.

(Crystalline phase)

The crystal phase (crystal structure) of the titanium oxide powder of the present embodiment is not particularly limited, and may be a single phase of any one of an anatase type, a rutile type, and a bruchite, or a mixed phase of these. Among these, the anatase type is preferable for the crystal phase of the titanium oxide powder of the present embodiment.

If the crystalline phase of the titanium oxide powder is an anatase type, the hiding power is higher when a cosmetic containing titanium oxide powder is applied to the skin, and when mixed with a cosmetic base, a color close to the tone of human skin is obtained. Is advantageous in

That the titanium oxide powder is an anatase type can be confirmed by, for example, an X-ray diffraction apparatus (brand name: X'Pert PRO, manufactured by Spectris). If the measurement result by the X-ray diffraction apparatus is an anatase single phase, the titanium oxide powder is an anatase type.

(Surface treatment)

The titanium oxide powder and titanium oxide particles of the present embodiment may have either an inorganic compound or an organic compound on the surface.

As a method of attaching either an inorganic compound or an organic compound to the surface of the titanium oxide particles, for example, a method of performing a surface treatment using a surface treatment agent may be mentioned.

The surface treatment agent is not particularly limited as long as it can be used for cosmetics, and may be appropriately selected according to the purpose. As a surface treatment agent, an inorganic component, an organic component, etc. are mentioned, for example.

As an inorganic component, silica, alumina, etc. are mentioned, for example.

Examples of the organic component include silicone compounds, organopolysiloxanes, fatty acids, fatty acid soaps, fatty acid esters, organic titanate compounds, surfactants, and non-silicone compounds. These may be used individually by 1 type, and may use 2 or more types together.

Examples of the silicone compound include silicone oils such as methylhydrogenpolysiloxane, dimethylpolysiloxane, and methylphenylpolysiloxane; Alkyl silanes such as methyl trimethoxysilane, ethyl trimethoxysilane, hexyl trimethoxysilane, and octyl trimethoxysilane; Fluoroalkylsilanes such as trifluoromethylethyltrimethoxysilane and heptadecafluorodecyltrimethoxysilane; Methicone, hydrogendimethicone, triethoxysilylethylpolydimethylsiloxyethyldimethicone, triethoxysilylethylpolydimethylsiloxyethylhexyldimethicone, (acrylate/tridecyl acrylic acid/methacrylic acid Triethoxysilylpropyl/dimethacrylic acid dimethicone) copolymer, triethoxycaprylylsilane, and the like. Moreover, as a silicone compound, the monomer of a compound may be sufficient, and a copolymer may be sufficient. These may be used individually by 1 type, and may use 2 or more types together.

Examples of fatty acids include palmitic acid, isostearic acid, stearic acid, lauric acid, myristic acid, behenic acid, oleic acid, rosinic acid, and 12-hydroxystearic acid.

As fatty acid soap, aluminum stearate, calcium stearate, aluminum 12-hydroxystearate, etc. are mentioned, for example.

Examples of the fatty acid ester include dextrin fatty acid ester, cholesterol fatty acid ester, sucrose fatty acid ester, and starch fatty acid ester.

Examples of the organic titanate compound include isopropyltriisostearoyl titanate, isopropyldimethacrylisostearoyl titanate, isopropyltri(dodecyl)benzenesulfonyl titanate, neopentyl (diallyl ) Oxy-tri(dioctyl)phosphate titanate, neopentyl(diallyl)oxy-trineododecane oil titanate, etc. are mentioned.

According to the titanium oxide powder of the present embodiment, when a cosmetic containing titanium oxide powder is applied to the skin, it is possible to obtain a natural finish with reduced bluishness peculiar to titanium oxide particles while maintaining both hiding power and clarity. In addition, when the cosmetic composition containing the titanium oxide powder of the present embodiment is applied to the skin, the spreadability and adhesion to the skin are excellent. Therefore, the titanium oxide powder of this embodiment can be suitably used for cosmetics, and can be particularly suitably used for base makeup cosmetics.

[Method for producing titanium oxide powder]

In the method for producing a titanium oxide powder of the present invention, a reaction solution is prepared by mixing a hydrolysis product of a titanium alkoxide or a titanium metal salt and a compound having a five-membered ring containing nitrogen, and the reaction solution is hydrothermally synthesized to obtain titanium oxide particles. It has a first process of generating. In addition, the method for producing titanium oxide powder of the present invention is, if necessary, by mixing a reaction solution containing titanium oxide particles after hydrothermal synthesis obtained in the first step and the same reaction solution as in the first step before hydrothermal synthesis, It has a second process of synthesis. In addition, the method for producing titanium oxide powder of the present invention has a third step of oxidizing the reaction solution obtained in the first step or the second step. Moreover, the manufacturing method of the titanium oxide powder of this invention has a 4th process of drying the solution after the 3rd process at 400 degreeC or less.

(The first step)

The first step is a step of producing titanium oxide particles.

The first step is a step of preparing a reaction solution by mixing a hydrolysis product of a titanium alkoxide or a titanium metal salt and a compound having a five-membered ring containing nitrogen, and hydrothermal synthesis of the reaction solution to produce titanium oxide particles.

(Hydrolysis product of titanium alkoxide or titanium metal salt)

The hydrolysis product of a titanium alkoxide or a titanium metal salt is obtained by hydrolyzing a titanium alkoxide or a titanium metal salt.

The hydrolysis product is, for example, a white solid cake-like solid, and is a hydrous titanium oxide called meta-titanic acid or ortho-titanic acid.

Examples of the titanium alkoxide include tetraethoxy titanium, tetraisopropoxy titanium, tetranormal propoxy titanium, and tetranormal butoxy titanium. These may be used individually by 1 type, and may use 2 or more types together. Among these, tetraisopropoxy titanium and tetranormal butoxy titanium are preferable, and tetraisopropoxy titanium is more preferable from the viewpoint of easy availability and easy control of the hydrolysis rate.

As titanium metal salt, titanium tetrachloride, titanium sulfate, etc. are mentioned, for example. These may be used individually by 1 type, and may use 2 or more types together.

In addition, in this embodiment, in order to obtain a high-purity anatase type titanium oxide particle, it is preferable to use a high-purity titanium alkoxide or a high-purity titanium metal salt.

Hydrolysis products contain by-products, such as alcohols, hydrochloric acid, and sulfuric acid.

Since by-products inhibit nucleation and crystal growth of titanium oxide particles, it is preferable to wash the hydrolysis product with pure water.

Examples of the cleaning method of the hydrolyzed product include decantation, Nutsche method, and ultrafiltration method.

(Compound having a five-membered ring containing nitrogen)

The compound having a five-membered ring containing nitrogen is included in the reaction solution because of its function as a pH adjuster of the reaction solution and as a catalyst for hydrothermal synthesis.

Examples of the compound having a nitrogen-containing five-membered ring include pyrrole, imidazole, indole, purine, pyrrolidine, pyrazole, triazole, tetrazole, isothiazole, isoxazole, furazane, carbazole, 1 , 5-diazabicyclo-[4.3.0]-5-nonene, etc. are mentioned. These may be used individually by 1 type, and may use 2 or more types together.

Among these, the compound having a five-membered ring containing nitrogen is preferably a compound containing one nitrogen atom from the viewpoint of narrowing the particle size distribution of the titanium oxide powder and further improving crystallinity. For example, pyrrole, indole, pyrrolidine, isothiazole, isoxazole, furazane, carbazole, and 1,5-diazabicyclo-[4.3.0]-5-nonene are preferred.

Among these, as the compound having a five-membered ring containing nitrogen, since the particle size distribution of the titanium oxide powder can be narrowed and crystallinity can be further improved, it contains one nitrogen atom, and the five-membered ring has a saturated heterocyclic structure. It is more preferable that it is a compound to have. For example, pyrrolidine and 1,5-diazabicyclo-[4.3.0]-5-nonene are more preferable.

It does not specifically limit as a method of preparing a reaction solution, It can select suitably according to a purpose. For example, a method of mixing using a stirrer, a bead mill, a ball mill, an attritor, a dissolver, etc. are mentioned.

In addition, water may be added to the reaction solution to adjust the concentration of the reaction solution. As water added to the reaction solution, deionized water, distilled water, pure water, etc. are mentioned, for example.

The pH of the reaction solution is preferably 9 or more and 13 or less, and more preferably 11 or more and 13 or less, from the point that the catalytic action of the compound having a five-membered ring containing nitrogen functions properly and the nucleation rate is appropriate. desirable.

When the pH of the reaction solution is in the range of 9 or more and 13 or less, the efficiency of production of titanium oxide particles and crystal growth becomes good.

The pH of the reaction solution can be adjusted by controlling the content of the compound having a five-membered ring containing nitrogen.

The concentration of titanium atoms in the reaction solution can be appropriately selected depending on the size of the titanium oxide particles of interest, preferably 0.05 mol/L or more and 3.0 mol/L or less, 0.5 mol/L or more, and 2.5 mol/L. It is more preferable that it is L or less.

When the titanium atom concentration in the reaction solution is 0.05 mol/L or more and 3.0 mol/L or less, the nucleation rate becomes appropriate, so that the production of titanium oxide particles and the efficiency of crystal growth are improved.

The concentration of titanium atoms in the reaction solution can be adjusted by controlling the content of the titanium alkoxide or the hydrolysis product of the titanium metal salt.

The molar ratio of the titanium atom and the compound having a five-membered ring containing nitrogen (a titanium atom: a compound having a five-membered ring containing nitrogen) in the reaction solution is preferably 1.0:0.01 to 1.0:2.0. If the molar ratio of the titanium atom and the compound having a five-membered ring containing nitrogen in the reaction solution is within the above range, titanium oxide particles having 8 or more surfaces can be produced.

For example, in the case of producing star-shaped titanium oxide particles, the molar ratio of the titanium atom: the compound having a five-membered ring containing nitrogen is preferably 1.0:0.01 to 1.0:1.0, and 1.0:0.1 to 1.0: It is more preferably 0.7.

In addition, in the case of producing octahedral titanium oxide particles, the molar ratio of the titanium atom: the compound having a five-membered ring containing nitrogen is preferably 1.0:0.5 to 1.0:2.0, and 1.0:0.6 to 1.0:1.8. It is more preferable and it is still more preferable that it is 1.0:0.7-1.0:1.5.

The hydrothermal synthesis is a method of heating a reaction solution and reacting titanium in the reaction solution in the presence of hot water at high temperature and high pressure. The reaction of hydrothermal synthesis is preferably carried out in a sealed container that can withstand high temperatures and high pressures.

Hydrothermal synthesis is carried out by placing the reaction solution in a high-temperature, high-pressure container called an autoclave, sealing it, and heating it in the autoclave.

When the reaction solution is heated, the moisture in the reaction solution evaporates, so that the pressure in the container increases, and a high-temperature, high-pressure reaction can be performed.

The heating and holding temperature in hydrothermal synthesis is preferably 150°C or higher and 350°C or lower, and more preferably 150°C or higher and 210°C or lower.

When the heating and holding temperature in hydrothermal synthesis is within the above range, the solubility of the titanium alkoxide or the hydrolysis product of the titanium metal salt in water is improved, and it can be dissolved in the reaction solution. Further, the nuclei of titanium oxide particles can be generated, the nuclei can be grown, and titanium oxide particles having a desired shape can be produced.

The heating rate in hydrothermal synthesis is not particularly limited and can be appropriately selected according to the purpose.

In addition, the pressure in hydrothermal synthesis is a pressure when the reaction solution is heated in the above temperature range in a high-temperature and high-pressure container.

In addition, during heating in an autoclave, it is preferable to stir the reaction solution using a stirring device.

The stirring speed is not particularly limited and can be appropriately selected according to the purpose, but it is preferably 100 rpm or more and 300 rpm or less.

The heating holding time in hydrothermal synthesis is not particularly limited, and can be appropriately selected depending on the size of the titanium oxide particles to be produced, but 3 hours or more is preferable, and 4 hours or more is more preferable.

If the heating holding time is less than 3 hours, the raw material titanium alkoxide or the hydrolysis product of the titanium metal salt does not react, and the yield may decrease.

The heating holding time is affected by the kind and concentration of the raw material. Therefore, a preliminary experiment is appropriately carried out, and it is sufficient to carry out the heating holding time at which the titanium oxide particles reach a desired size. For example, the heating holding time may be 9 hours, 12 hours, 24 hours, 48 hours, or 72 hours. However, from the viewpoint of production efficiency, heating may be stopped when the titanium oxide particles reach a desired size.

(2nd process)

The second step is a step of further crystallizing the titanium oxide particles obtained in the first step. The second step is performed when the size of the obtained titanium oxide particles is smaller than that desired.

In the second step, a reaction solution containing titanium oxide particles after hydrothermal synthesis obtained in the first step and the same reaction solution as the first step before hydrothermal synthesis (a hydrolysis product of a titanium alkoxide or a titanium metal salt, and a five-membered ring containing nitrogen) It is a process of mixing a compound) to perform hydrothermal synthesis.

A reaction solution containing titanium oxide particles after hydrothermal synthesis obtained in the first step and the same reaction solution as in the first step before hydrothermal synthesis (a hydrolysis product of titanium alkoxide or titanium metal salt, and a compound having a five-membered ring containing nitrogen) The mixing ratio is preferably 1:1 to 1:20 in terms of the mass of the titanium oxide particles.

Hydrothermal synthesis in the second step can be performed under the same conditions as in the first step.

In the case of making the titanium oxide particles obtained in the second process larger, the reaction solution containing the titanium oxide particles after hydrothermal synthesis obtained in the second process and the same reaction solution as in the first process before hydrothermal synthesis (titanium alkoxide or titanium metal salt) And a compound having a five-membered ring containing nitrogen) may be mixed, and hydrothermal synthesis may be performed under the same conditions as in the first step. Further, the same process may be repeated one or more times until titanium oxide particles having a desired size are obtained.

(3rd process)

The third step is a step of oxidizing the reaction solution obtained in the first step or the second step.

The oxidizing method is not particularly limited as long as it is a method capable of decomposing a compound having a five-membered ring containing nitrogen. For example, ozone treatment or an oxidation process using hydrogen peroxide can be used.

Regarding ozone treatment, a treatment method is described in detail in the ozone handbook (Japan Ozone Association), for example.

Titanium oxide having an L value of 75 or more can be obtained by decomposing a compound having a five-membered ring containing nitrogen by an oxidation process.

(Step 4)

After performing the third step, the method of taking out the titanium oxide powder from the solution is not particularly limited, and can be appropriately selected depending on the purpose. As a method of taking out titanium oxide from the solution, a method of solid-liquid separation such as decantation and the nuche method may be mentioned.

Further, after taking out the titanium oxide powder, for the purpose of reducing impurities, the obtained titanium oxide powder may be washed with pure water or the like.

The titanium oxide powder taken out by solid-liquid separation may be naturally dried or heated at 400°C or lower and dried.

The lower limit of the heating temperature of the titanium oxide powder is not particularly limited as long as the titanium oxide powder can be dried. For example, 200 degreeC may be sufficient, 250 degreeC may be sufficient, and 300 degreeC may be sufficient.

By drying the titanium oxide powder at 400°C or less, it is possible to obtain a titanium oxide powder having excellent spreadability and adhesion to the skin when applied to the skin.

When the drying temperature becomes high, titanium oxide particles are fused together, and the feeling when applied to the skin is also deteriorated, which is not preferable.

The titanium oxide powder of the present embodiment can be obtained by taking out the titanium oxide powder from the reaction solution after hydrothermal synthesis and drying at 400°C or less. The obtained titanium oxide powder can be stored in a preferred method selected as needed.

Further, the titanium oxide powder may be subjected to a surface treatment. The timing of performing the surface treatment is not particularly limited, and can be appropriately selected according to the purpose. As the timing for performing the surface treatment, for example, after the first step or after the second step.

The method of surface treatment is not particularly limited, and a known method can be appropriately selected according to the kind of the surface treatment agent to be used.

[Dispersion]

The dispersion liquid of this embodiment contains the titanium oxide powder and a dispersion medium of this embodiment. The dispersion liquid of this embodiment contains other components as needed.

The dispersion liquid of the present embodiment may be a low viscosity liquid or a high viscosity paste.

The content of the titanium oxide powder in the dispersion of this embodiment is not particularly limited, and can be appropriately selected according to the purpose. For example, the content of the titanium oxide powder is 0.1 mass% or more, 90 mass% or less, 1 mass% or more, 80 mass% or less, 5 mass% or more with respect to the total amount of the dispersion of this embodiment. Moreover, 70 mass% or less, 10 mass% or more, 60 mass% or less, 20 mass% or more, and 50 mass% or less may be sufficient.

(Dispersion medium)

The dispersion medium is not particularly limited as long as it can be blended into a cosmetic, and may be appropriately selected according to the purpose. As the dispersion medium, for example, water, alcohols, esters, ethers, ketones, hydrocarbons, amides, polysiloxanes, modified products of polysiloxanes, hydrocarbon oils, ester oils, higher fatty acids, higher alcohols, etc. Can be lifted. These may be used individually by 1 type, and may use 2 or more types together.

As alcohols, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, octanol, glycerin, etc. are mentioned, for example.

Examples of esters include ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and γ-butyrolactone.

Examples of ethers include diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), and ethylene glycol monobutyl ether (Butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, etc. are mentioned.

As ketones, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetyl acetone, cyclohexanone, etc. are mentioned, for example.

Examples of hydrocarbons include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; Cyclic hydrocarbons, such as cyclohexane, etc. are mentioned.

Examples of amides include dimethylformamide, N,N-dimethylacetoacetamide, and N-methylpyrrolidone.

Examples of the polysiloxanes include chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and diphenylpolysiloxane; Cyclic polysiloxanes, such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane, etc. are mentioned.

As a modified product of polysiloxanes, amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, fluorine-modified polysiloxane, etc. are mentioned, for example.

Examples of the hydrocarbon oil include liquid paraffin, squalane, isoparaffin, branched light paraffin, petrolatum, ceresin, and the like.

As ester oil, isopropyl myristate, cetyl isooctanoate, glyceryl trioctanoate, etc. are mentioned, for example.

Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, and stearic acid.

As a higher alcohol, lauryl alcohol, cetyl alcohol, stearyl alcohol, hexyldodecanol, isostearyl alcohol, etc. are mentioned, for example.

(Other ingredients)

Other components are not particularly limited as long as they do not impair the effect of the dispersion liquid of the present embodiment, and may be appropriately selected according to the purpose. Examples of other components include dispersants, stabilizers, water-soluble binders, thickeners, oil-soluble preservatives, ultraviolet absorbers, oil-soluble drugs, oil-soluble pigments, oil-soluble proteins, vegetable oils, and animal oils. These may be used individually by 1 type, and may use 2 or more types together.

The content of the dispersion medium is not particularly limited, and can be appropriately selected according to the purpose. The content of the dispersion medium is preferably 10% by mass or more and 99% by mass or less, more preferably 20% by mass or more and more preferably 90% by mass or less, and 30% by mass or more based on the total amount of the dispersion liquid of the present embodiment. It is more preferable that it is 80 mass% or less.

According to the dispersion liquid of the present embodiment, when the cosmetic composition containing the dispersion liquid of the present embodiment is applied to the skin, it is possible to obtain a natural finish with reduced bluishness peculiar to titanium oxide particles while maintaining both hiding power and clarity. In addition, when the cosmetic composition containing the titanium oxide powder of the present embodiment is applied to the skin, the spreadability and adhesion to the skin are excellent. Therefore, the dispersion liquid of this embodiment can be suitably used for cosmetics, and can be especially suitably used for base makeup cosmetics.

[Method of preparing dispersion]

The method for producing the dispersion of the present embodiment is not particularly limited, and a known method can be employed. As a manufacturing method of the dispersion liquid of the present embodiment, for example, a method of preparing a dispersion liquid by mechanically dispersing the titanium oxide powder of the present embodiment in a dispersion medium with a dispersing device may be mentioned.

Examples of the dispersing device include a stirrer, a magnetoelectric mixer, a homomixer, an ultrasonic homogenizer, a sand mill, a ball mill, and a roll mill.

When the dispersion liquid of this embodiment is applied to the skin, it is possible to reduce the bluishness peculiar to titanium oxide while maintaining both hiding power and clarity. In addition, when the cosmetic composition containing the titanium oxide powder of the present embodiment is applied to the skin, the spreadability and adhesion to the skin are excellent.

[Cosmetics]

The cosmetic composition of this embodiment contains the titanium oxide powder of this embodiment and a cosmetic base. The cosmetic of this embodiment contains other components as necessary.

Although the content of the titanium oxide powder in the cosmetic can be arbitrarily selected, it is preferably 0.1% by mass or more and 50% by mass or less with respect to the entire cosmetic. For example, it may be 0.1 to 5% by mass, 5 to 15% by mass, 15 to 35% by mass, or 35 to 50% by mass.

(Cosmetic base)

As the cosmetic base, it can be appropriately selected from those commonly used in cosmetics, and examples thereof include talc and mica. These may be used individually by 1 type, and may use 2 or more types together.

The content of the cosmetic base material in the cosmetic is not particularly limited and can be appropriately selected according to the purpose.

(Other ingredients)

In addition to the titanium oxide powder of the present embodiment and the cosmetic base, the cosmetic of the present embodiment may contain other components within a range that does not impair the effect of the present embodiment.

Other components can be appropriately selected from those commonly used in cosmetics. Examples of other components include solvents, emulsions, surfactants, moisturizers, organic ultraviolet absorbers, antioxidants, thickeners, fragrances, colorants, physiologically active ingredients, and antibacterial agents. These may be used individually by 1 type, and may use 2 or more types together.

The content of the other components in the cosmetic is not particularly limited, and can be appropriately selected according to the purpose.

The method for producing the cosmetic according to the present embodiment is not particularly limited, and can be appropriately selected depending on the purpose. The manufacturing method of the cosmetic composition of the present embodiment includes, for example, a method of mixing titanium oxide powder with a cosmetic base and mixing other ingredients, a method of manufacturing by mixing titanium oxide powder with an existing cosmetic, and a dispersion. A method of mixing with a cosmetic base, mixing other ingredients, and a method of mixing a dispersion with an existing cosmetic.

(shape)

The form of the cosmetic of the present embodiment is not particularly limited, and can be appropriately selected according to the purpose. Examples of the form of the cosmetic composition of the present embodiment include powder, solid powder, solid, liquid, and gel. In addition, when the form of the cosmetic is liquid or gel, the form of dispersion of the cosmetic is not particularly limited, and can be appropriately selected according to the purpose. As a dispersion form of a gel-like cosmetic, a water-in-oil type (W/O type) emulsion, an oil-in-water type (O/W type) emulsion, an oil type, etc. are mentioned, for example.

Examples of the cosmetic composition of the present embodiment include base makeup, nail polish, and lipstick. Among these, base makeup is preferable.

As a base makeup, for example, a makeup base mainly used to reduce unevenness of the skin, a foundation mainly used to adjust the tone of the skin, and mainly used to improve the fixation of the foundation on the skin. Face powder, etc. are mentioned.

According to the cosmetic of this embodiment, when applied to the skin, it is possible to reduce the bluishness peculiar to titanium oxide particles while having a hiding power and a sense of transparency. In addition, when the cosmetic composition containing the titanium oxide powder of the present embodiment is applied to the skin, the spreadability and adhesion to the skin are excellent.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1]

(Production of titanium oxide powder)

1 L of pure water was put in a 2 L glass container, and 1 mol of tetraisopropoxy titanium (trade name: A-1, manufactured by Nippon Soda Corporation) was added dropwise while stirring to obtain a white suspension containing a hydrolysis product of titanium alkoxide.

Next, the white suspension was separated into a solid-liquid solution to obtain a white cake (1 mol (80 g) in terms of titanium oxide) as a solid part of the hydrolysis product of titanium alkoxide.

Next, in an autoclave, pyrrolidine (manufactured by Kanto Chemical Co., Ltd.) in an amount of 0.7 mol and the obtained white cake were put, and pure water was added to make the total amount 1 kg. The sealed container was held at 260° C. for 9 hours to perform hydrothermal synthesis to obtain a reaction solution (B1) containing titanium oxide particles.

1 g of 0.1 mol/L NaOH aqueous solution was added to 100 g of the obtained reaction solution (B1). Next, ozone was supplied to this liquid using an ozone generator (trade name: ozone generator OS-1N type, manufactured by Mitsubishi Denki). Ozone was supplied by carrying out bubbling treatment for 3 hours using a Kerami filter at a supply amount of 1.2 g/h.

The reaction solution supplied with ozone was solid-liquid separated, and the solid was dried at 300° C. to obtain titanium oxide powder of Example 1.

(Measurement of BET specific surface area and average particle diameter converted from BET specific surface area)

The BET specific surface area of the titanium oxide powder of Example 1 was measured using a specific surface area meter (brand name: BELSORP-mini, manufactured by Nippon Bell Corporation). As a result, the BET specific surface area of the titanium oxide powder of Example 1 was 12 m ² /g.

Further, as described later, it was confirmed that the content rate of the octahedral particles was 70% by number or more.

The average particle diameter converted from the BET specific surface area of the titanium oxide powder of Example 1 was calculated by the following formula (1). As a result, the average particle diameter in terms of BET was 338 nm. Table 1 shows the results.

BET conversion average particle diameter (nm) = 16240/(BET specific surface area (m ² /g) x ρ (g/cm ³ ))... (One)

In addition, in the above formula (1), ρ represents the density of titanium oxide, and ρ is set to 4 g/cm ³ .

(Measurement of shape)

"Measurement of line segments connecting two opposite vertices, and content of octahedral particles"

2, the maximum value of the line segment connecting the two opposite vertices in one particle (hereinafter, referred to as (X)), and the two opposite vertices which are approximately orthogonal to the line segment related to the maximum value. Secondary electrons of the titanium oxide particles of Example 1 using a scanning electron microscope (SEM) (trade name: S-4800, manufactured by Hitachi High-Technologies Corporation) for the minimum value of the line segment (hereinafter referred to as (Y)). It was measured by observing the image. The SEM image is shown in FIG. 3.

Observing 100 octahedral particles contained in the titanium oxide particles of Example 1, the average value of (X), the average value of (Y), and the ratio of (X) to (Y) (X/Y ) Was calculated. As a result, the average value of (X) is 350 nm, and the value obtained by dividing the average value of (X) by the average particle diameter in terms of BET (hereinafter sometimes referred to as "average value of (X) / average particle diameter in terms of BET") is 1.0, The average value of the ratio (X/Y) was 2.0.

Moreover, as a result of observing 100 titanium oxide particles with a scanning electron microscope, the octahedral titanium oxide particles were present in 70% by number in the titanium oxide powder. Table 1 shows the results.

"Identification of the shape of titanium oxide particles"

The titanium oxide powder of Example 1 was observed with a transmission electron microscope (TEM) (product number: H-800, manufactured by Hitachi High-Technologies Corporation). The TEM image is shown in FIG. 4. Also in the TEM image, it was confirmed that octahedral titanium oxide particles were contained. Table 1 shows the results.

(Identification of the crystal phase of titanium oxide particles)

The crystal phase of the titanium oxide powder obtained in Example 1 was identified using an X-ray diffraction apparatus (trade name: X'Pert PRO, manufactured by Spectris Corporation). As a result, the titanium oxide powder of Example 1 was anatase single phase. Table 1 shows the results.

(Measurement of L value)

The L value of the titanium oxide powder of Example 1 was measured using a spectral variable angle colorimeter (brand name GC5000, manufactured by Nippon Denshoku Kogyo Co., Ltd.). As a result, the L value of the titanium oxide powder of Example 1 was 88.

"The production of cosmetics"

2 g of the titanium oxide powder of Example 1 and 8 g of talc were mixed to prepare a base makeup cosmetic of Example 1.

(Evaluation of bluishness, transparency, and hiding power)

The base makeup cosmetic of Example 1 was applied to a 5 cm square substrate (trade name: HELIOPLATE HD-6, manufactured by Helioscreen) so as to be 12 mg to 14 mg to prepare a coated substrate.

Using a spectrophotometer (product number; UV-3150, manufactured by Shimadzu Corporation), the diffuse transmission spectrum (TT), the diffuse reflection spectrum (TR), and the linear reflection spectrum (R) of the coated substrate were measured, and the following It evaluated using an index. In all, the incidence direction of light was measured from the coated surface, and the reflection spectrum was measured on the basis of a molded plate obtained by compressing barium sulfate powder (Kanto Chemical Co., Ltd.).

Table 1 shows the results.

The ratio of the diffuse reflectance at _{450 nm} (TR _{450 nm} ) and the diffuse reflectance at _{550 nm} (TR _{550 nm} ) (TR _{450 nm} /TR _{550 nm} ) was used as an index of bluishness. As the ratio becomes larger than 1, it can be said to be bluish, so the smaller the value of TR _450nm / TR _550nm is, the more preferable.

In addition, the correlation between the index of bluishness and the person's appearance is shown in Table 2.

(Transparency)

The ratio of the linear reflectance (R _{550 nm} ) at ₅₅₀ nm and the diffuse reflectance (TR _{550 nm} ) at _{550 nm} (R _{550 nm} / TR _{550 nm} ) was used as an index of transparency. The smaller the ratio is, the higher the transparency, so the smaller the value is, the more preferable.

In addition, the correlation between the index of transparency and the person's appearance is shown in Table 2.

(Hiding power)

The diffuse reflectance at _{550 nm} (TR _{550 nm} ) was used as an index of the hiding power. When it is large, since it can be said that the hiding power is large, it is preferable that the value is large.

In addition, the correlation between the index of hiding power and the person's appearance is shown in Table 2.

[Example 2]

In an autoclave, 100 g of a reaction solution (B1) containing titanium oxide particles obtained in the manufacturing process of Example 1 (8 g of titanium oxide), and a white cake obtained in the manufacturing process of Example 1 (1 mol (80 g) in terms of titanium oxide) ) And 0.7 mol of pyrrolidine were added, pure water was added to make the total amount 1 kg, and stirred to prepare a mixed solution.

Next, the container was sealed, and the mixture was held at 260° C. for 9 hours to crystallize titanium oxide particles to obtain a reaction solution (B2) containing titanium oxide particles.

Instead of using the reaction solution (B1), ozone was supplied to the reaction solution (B2) in exactly the same manner as in Example 1 except that the reaction solution (B2) was used.

The reaction solution supplied with ozone was solid-liquid separated, and the solid was dried at 300°C to obtain the titanium oxide powder of Example 2.

About the obtained titanium oxide powder of Example 2, the BET specific surface area, shape, crystal phase, and L value were measured in the same manner as in Example 1.

As a result, the BET specific surface area was 8 m ² /g, and the average particle diameter in terms of BET was 508 nm. The average value of (X) of the octahedral titanium oxide particles was 450 nm, the average value of (X)/average particle diameter in terms of BET was 0.9, and the average value of the ratio (X/Y) was 2.0. Table 1 shows the results.

Further, in the titanium oxide particles of Example 2, the octahedral titanium oxide particles were 65% by number of the total particles, and the crystal phase of the titanium oxide powder was anatase single phase. Table 1 shows the results.

Moreover, the L value of the titanium oxide powder of Example 2 was 88.

Instead of using the titanium oxide powder of Example 1, a base makeup cosmetic of Example 2 was obtained in the same manner as in Example 1 except that the titanium oxide powder of Example 2 was used.

In the same manner as in Example 1, the bluishness, transparency, and hiding power of the base makeup cosmetic of Example 2 were evaluated. Table 1 shows the results.

[Example 3]

After solid-liquid separation of the reaction solution containing the titanium oxide powder, a titanium oxide powder of Example 3 was obtained in the same manner as in Example 2, except that the solid was dried at 400°C instead of 300°C.

About the obtained titanium oxide powder of Example 3, the BET specific surface area, shape, crystal phase, and L value were measured in the same manner as in Example 1.

As a result, the BET specific surface area was 6 m ² /g, and the average particle diameter in terms of BET was 677 nm. The average value of (X) of the octahedral titanium oxide particles was 740 nm, the average value of (X)/average particle diameter in terms of BET was 1.1, and the average value of the ratio (X/Y) was 2.0. Table 1 shows the results.

Further, in the titanium oxide particles of Example 3, the octahedral titanium oxide particles were 65% by number of the total particles, and the crystal phase of the titanium oxide powder was anatase single phase. Table 1 shows the results.

Moreover, the L value of the titanium oxide powder of Example 3 was 88. Table 1 shows the results.

Further, in the same manner as in Example 1, the bluishness, transparency, and hiding power of the base makeup cosmetic of Example 3 were evaluated. Table 1 shows the results.

[Example 4]

To 100 g of the reaction solution (B1) obtained in the production process of Example 1, 1 g of 0.1 mol/L NaOH aqueous solution and 100 g of hydrogen peroxide water (concentration 30%) were added. Then, this liquid was stirred at 80 degreeC for 3 hours.

The reaction solution after stirring was solid-liquid separated, and the solid was dried at 300°C to obtain the titanium oxide powder of Example 4.

With respect to the obtained titanium oxide powder of Example 4, the BET specific surface area, shape, crystal phase, and L value were measured in the same manner as in Example 1.

As a result, the BET specific surface area was 13 m ² /g, and the average particle diameter in terms of BET was 312 nm. The average value of (X) of the octahedral titanium oxide particles was 350 nm, the average value of (X)/average particle diameter in terms of BET was 1.1, and the average value of the ratio (X/Y) was 2.0. Table 1 shows the results.

In addition, in the titanium oxide particles of Example 4, the octahedral titanium oxide particles were 70% by number of the total particles, and the crystal phase of the titanium oxide powder was anatase single phase. Table 1 shows the results.

Moreover, the L value of the titanium oxide powder of Example 4 was 81.

Instead of using the titanium oxide powder of Example 1, a base makeup cosmetic of Example 4 was obtained in the same manner as in Example 1 except that the titanium oxide powder of Example 4 was used.

In the same manner as in Example 1, the bluishness, transparency, and hiding power of the base makeup cosmetic of Example 4 were evaluated. Table 1 shows the results.

[Comparative Example 1]

The reaction solution (B1) obtained in the manufacturing process of Example 1 was solid-liquid separated, and the solid was dried at 300°C to obtain the titanium oxide powder of Comparative Example 1 not subjected to ozone treatment.

With respect to the obtained titanium oxide powder of Comparative Example 1, the BET specific surface area, shape, crystal phase, and L value were measured in the same manner as in Example 1.

As a result, the BET specific surface area was 12 m ² /g, and the average particle diameter in terms of BET was 338 nm. The average value of (X) of the octahedral titanium oxide particles was 350 nm, the average value of (X) / average particle diameter in terms of BET was 1.0, and the average value of the ratio (X/Y) was 2.0. Table 1 shows the results.

In addition, the octahedral titanium oxide particles in the titanium oxide particles of Comparative Example 1 were 70% by number with respect to the total particles, and the crystal phase of the titanium oxide powder was anatase single phase. Table 1 shows the results.

Moreover, the L value of the titanium oxide powder of Comparative Example 1 was 70.

Instead of using the titanium oxide powder of Example 1, a base makeup cosmetic of Comparative Example 1 was obtained in the same manner as in Example 1 except that the titanium oxide powder of Comparative Example 1 was used.

In the same manner as in Example 1, the bluishness, transparency, and hiding power of the base makeup cosmetic of Comparative Example 1 were evaluated. Table 1 shows the results.

[Comparative Example 2]

A commercially available titanium oxide particle having an average diameter of 300 nm and a spherical rutile type having a BET specific surface area of 6 m ² /g was used as the titanium oxide particle of Comparative Example 2.

Moreover, the average particle diameter in terms of BET was calculated by the following (2) formula. Since the particles are spherical, equation (2), which is different from equation (1), was used in the calculation. As a result, the average particle diameter in terms of BET was 250 nm, and the value obtained by dividing the average particle diameter by the average particle diameter in terms of BET was 1.2.

BET conversion average particle diameter (nm) = 6000/(BET specific surface area (m ² /g) x ρ (g/cm ³ ))... (2)

In addition, in said formula (2), since ρ represents the density of titanium oxide, it was set as ρ = 4 g/cm ³ .

The average particle diameter converted from the BET specific surface area of the spherical particles substantially coincides with the primary particle average diameter.

Further, in the titanium oxide particles of Comparative Example 2, the average value of (X) was 300 nm, the average value of (X)/average particle diameter in terms of BET was 1.2, and the average value of the ratio (X/Y) was 1.0. Table 1 shows the results.

Further, since the titanium oxide particles were spherical, the diameter of the sphere was used as the values of (X) and (Y). Specifically, in the spherical titanium oxide particles, the diameter at an arbitrary position corresponds to the maximum value (X) of a line segment connecting two opposite vertices in one particle. In the spherical titanium oxide particles, the minimum value (Y) of the line segment connecting two opposite vertices, wherein the other diameter approximately orthogonal to the diameter at the arbitrary position is approximately orthogonal to the line segment with respect to the maximum value (X). Corresponds to

In addition, the content rate of the octahedral titanium oxide particles in the titanium oxide particles of Comparative Example 2 was 0% by number with respect to the total particles. Table 1 shows the results.

Instead of using the titanium oxide powder of Example 1, a base makeup cosmetic of Comparative Example 2 was obtained in the same manner as in Example 1 except that the titanium oxide powder of Comparative Example 2 was used.

It carried out similarly to Example 1, and evaluated the bluishness, transparency, and hiding power. Table 1 shows the results.

[Comparative Example 3]

Commercially available titanium oxide particles were used as the titanium oxide powder of Comparative Example 3.

In this titanium oxide particle, the primary particles are spheroids having an average long diameter of 100 nm and an average short diameter of 30 nm, and the average long diameter (average aggregated long diameter) at which the primary particles aggregated is 300 nm, and the average short diameter (average aggregated short diameter) is 136 nm, It had a spindle shape with an average value of agglomerated long diameter/agglomerated short diameter of 2.2, and a rutile type having a BET specific surface area of 21 m ² /g.

Since the shape of the primary particles is a spheroid, the average particle diameter in terms of BET was obtained using the following equation (3), which is different from the equation (1). Specifically, it was calculated as P = 50 nm (100 nm ÷ 2) and Q = 3.33 (100 ÷ 30) by the following (3) equation. As a result, the average particle diameter in terms of BET was 100 nm.

BET specific surface area (m ² /g)=1000×(1+P/((1-(1-(1/Q) ² )) ^1/2 ×P×(1-(1/Q) ² ) ^{1/ 2} ×sin ^-1 ((1-(1/Q) ² ) ^1/2 ))/(2×ρ×P/3)…(3)

In addition, in the above formula (3), ρ represents the density of titanium oxide, and ρ is set to 4 g/cm ³ .

In addition, in the above formula (3), P represents the radius (nm) of the average major diameter of the spheroid that is the primary particle, Q represents the radius of the major axis (major diameter/2 of the primary particle), and the radius of the minor axis ( It shows the average value of the aspect ratio divided by the short diameter/2) of a primary particle.

Further, in the titanium oxide particles of Comparative Example 3, the average value of (X) was 300 nm, the average value of (X)/average particle diameter in terms of BET was 3.0, and the average value of the ratio (X/Y) was 2.2. Table 1 shows the results.

In addition, since the spindle-shaped titanium oxide particles of Comparative Example 3 are aggregated, the average long diameter (average aggregated long diameter) corresponds to the maximum value X, and the average short diameter (which is approximately orthogonal to the line segment related to the maximum value X) ( The average aggregation short diameter) corresponds to the minimum value (Y).

The value obtained by dividing the long aggregate diameter by the average particle diameter in terms of BET was 3.0. Table 1 shows the results.

Since the titanium oxide particles of Comparative Example 3 were agglomerated, the long diameter of the agglomerate and the average particle diameter converted from the BET specific surface area were separated, resulting in a result that the long diameter of the agglomerate / average particle diameter in terms of BET exceeded 2.5.

In addition, the content rate of the octahedral titanium oxide particles in the titanium oxide particles of Comparative Example 3 was 0% by number with respect to the total particles. Table 1 shows the results.

Instead of using the titanium oxide powder of Example 1, a base makeup cosmetic of Comparative Example 3 was obtained in the same manner as in Example 1 except that the titanium oxide powder of Comparative Example 3 was used.

It carried out similarly to Example 1, and evaluated the bluishness, transparency, and hiding power. Table 1 shows the results.

By comparing Examples 1 to 4 with Comparative Example 1, it was confirmed that the titanium oxide powder obtained through the oxidation process was excellent in whiteness.

In addition, by comparing Examples 1 to 4 with Comparative Examples 2 and 3, the specific surface area is 5 m ² /g or more, 15 m ² /g or less, and polyhedral titanium oxide particles having 8 or more faces. It was confirmed that the bluishness peculiar to titanium oxide was reduced, while making the titanium oxide powder containing a concealing power and transparency compatible. Therefore, it became clear that the titanium oxide powder of this embodiment is suitable for the cosmetic composition for base makeup.

In order to confirm that the octahedral titanium oxide particles can scatter light widely, the following simulation was performed.

For a spherical titanium oxide particle having a diameter of 500 nm and an octahedral titanium oxide particle having a maximum distance between two opposite vertices in one particle, when irradiating each of these particles with light having a wavelength of 700 nm, The scattering of light was simulated by the FDTD method (Finite-difference time-domain method). Fig. 5 shows the simulation results for the spherical titanium oxide particles. Further, the simulation results of the octahedral titanium oxide particles are shown in FIG. 6.

In Figs. 5 and 6, it is assumed that titanium oxide particles are present in the center of the square display surface. Therefore, in this simulation, it can be said that the scattering degree is large when the scattering light is diffused more (widely) when the titanium oxide particles present in the center of the display surface are irradiated with light. On the other hand, in this simulation, it can be said that the scattering degree is small when the light irradiated with the titanium oxide particles present in the center on the display surface does not diffuse, or if the diffusion is small.

From the results of Figs. 5 and 6, it was confirmed that the octahedral titanium oxide particles scatter light to a distance approximately twice as long as the spherical titanium oxide particles. This result shows that by making the shape of a particle into an octahedral shape, light is scattered widely, and a hiding power and a sense of transparency can be made compatible.

The titanium oxide powder of the present invention contains polyhedral titanium oxide particles having a BET specific surface area of 5 m ² /g or more and 15 m ² /g or less and having 8 or more faces, and the L value in the Lab color space is Since it is 75 or more, when applied to the skin, it is possible to reduce the bluishness peculiar to titanium oxide particles while having a hiding power and a sense of transparency. And it is excellent in color tone as a cosmetic. Therefore, it can be suitably used for a base makeup cosmetic such as a foundation. Further, since the titanium oxide powder of the present invention is also excellent in performance as a white pigment, it can also be used for industrial applications such as white ink, and its industrial value is large.

X: The maximum value of a line segment connecting two opposite vertices
Y: The minimum value of a line segment connecting two vertices that is approximately orthogonal to the line segment with respect to the maximum value of the distance between two opposite vertices

Claims (9)

As a titanium oxide powder having a BET specific surface area of 5 m ² /g or more and 15 m ² /g or less,
The titanium oxide powder comprises polyhedral titanium oxide particles having 8 or more faces,
Titanium oxide powder, characterized in that the L value in Lab color space is 75 or more. The method according to claim 1,
The polyhedral titanium oxide particles,
As an octahedral titanium oxide particle,
One octahedral titanium oxide particle has a plurality of line segments connecting two opposite vertices and the maximum value of their length,
A titanium oxide powder, wherein the average value of the maximum values of the plurality of octahedral titanium oxide particles is 300 nm or more and 1000 nm or less. The method according to claim 2,
A titanium oxide powder, characterized in that a value obtained by dividing the average value of the maximum value by the average particle diameter converted from the BET specific surface area (average value of the maximum value/average particle diameter in terms of BET) is 0.5 or more and 2.5 or less. The method according to any one of claims 1 to 3,
The titanium oxide powder, wherein the content of the polyhedral titanium oxide particles in the titanium oxide powder is 50% by number or more. The method according to any one of claims 1 to 4,
Titanium oxide powder, characterized in that it has either an inorganic compound or an organic compound on its surface. A dispersion liquid comprising the titanium oxide powder according to any one of claims 1 to 5 and a dispersion medium. A cosmetic comprising the titanium oxide powder according to any one of claims 1 to 5 and a cosmetic base. The method according to claim 1,
The polyhedral shape having 8 or more faces is an octahedral shape in which two congruent square pyramids share a square bottom surface,
The titanium oxide powder, characterized in that the titanium oxide powder contains at least 60% by number of the octahedral titanium oxide particles. The method according to claim 1,
The octahedral particle has a bisagonal pyramid shape in which two congruent square pyramids share a square bottom surface,
The tip of the bisagonal pyramid is any one of a pointed shape, roundness, and flat shape, titanium oxide powder.

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